Toy building block



FIG. 1 is a front perspective view of a toy building block embodying our design;

FIG. 2 is a left side view of FIG. 1;

FIG. 3 is a side view of FIG. 1 viewed from the apex;

FIG. 4 is a side view of FIG. 1 showing the protrusion;

FIG. 5 is a side view of FIG. 1 showing the concavity;

FIG. 6 is a top plan view of FIG. 1; and,

FIG. 7 is a bottom view of FIG. 1 with broken lines.

The portion of a toy building block shown in broken lines form no part of the claimed design. 

CLAIM We claim the ornamental design for a toy building block, as shown and described. 